A positron emission tomography study of voluntarily and electrically contracted human quadriceps.
Vanderthommen, Marc ; ; Bauvir, Philippe et al
in Muscle & Nerve (1997), 20Detailed reference viewed: 5 (2 ULg)
Reversibility of thiamine deficiency-induced partial necrosis and mitochondrial uncoupling by addition of thiamine to neuroblastoma cell suspensions.
Bettendorff, Lucien ; Goessens, Guy ; Sluse, Francis
in Molecular and Cellular Biochemistry (1997), 174(1-2), 121-4
Culture of neuroblastoma cells in the presence of low thiamine concentration (16 nM) and of the transport inhibitor amprolium leads to the appearance of signs of necrosis: the chromatin condenses, the ... [more ▼]
Culture of neuroblastoma cells in the presence of low thiamine concentration (16 nM) and of the transport inhibitor amprolium leads to the appearance of signs of necrosis: the chromatin condenses, the oxygen consumption decreases and is uncoupled, the mitochondrial cristae are disorganized, the thiamine diphosphate-dependent dehydrogenase activities are impaired. When 10 microM thiamine are added to these cells, the basal respiration increases, the coupled respiration is restored and mitochondrial morphology is recovered within 1 h. Addition of succinate, which is oxidized via a thiamine diphosphate-independent dehydrogenase, to digitonin-permeabilized cells immediately restores a coupled respiration. Our results suggest that the slowing of the citric acid cycle is the cause of the biochemical lesion induced by severe thiamine deficiency and that part of the mitochondria remain functional. [less ▲]Detailed reference viewed: 28 (17 ULg)
Electron partitioning between the two branching quinol-oxidizing pathways in Acanthamoeba castellanii mitochondria during steady-state state 3 respiration.
; ; et al
in Journal of Biological Chemistry (1997), 273(17), 10174-10180
Amoeba mitochondria possess a respiratory chain with two quinol-oxidizing pathways: the cytochrome pathway and the cyanide-resistant alternative oxidase pathway. The ADP/O method, based on the non ... [more ▼]
Amoeba mitochondria possess a respiratory chain with two quinol-oxidizing pathways: the cytochrome pathway and the cyanide-resistant alternative oxidase pathway. The ADP/O method, based on the non-phosphorylating property of alternative oxidase, was used to determine contributions of both pathways in overall state 3 respiration in the presence of GMP (an activator of the alternative oxidase in amoeba) and succinate as oxidizable substrate. This method involves pair measurements of ADP/O ratios plus and minus benzohydroxamate (an inhibitor of the alternative oxidase). The requirements of the method are listed and verified. When overall state 3 respiration was decreased by increasing concentrations of n-butyl malonate (a non-penetrating inhibitor of succinate uptake), the quinone reduction level declined. At the same time, the alternative pathway contribution decreased sharply and became negligible when quinone redox state was lower than 50%, whereas the cytochrome pathway contribution first increased and then passed through a maximum at a quinone redox state of 58% and sharply decreased at a lower level of quinone reduction. This study is the first attempt to examine the steady-state kinetics of the two quinol-oxidizing pathways when both are active and to describe electron partitioning between them when the steady-state rate of the quinone-reducing pathway is varied. [less ▲]Detailed reference viewed: 9 (4 ULg)
Consequences of cold and warm ischemia on pulmonary mitochondrial respiratory function.
Detry, Olivier ; ; Lambermont, Bernard et al
in Transplantation Proceedings (1997), 29
IN RECENT years, pulmonary transplantation has become the treatment of choice for several end-stage lung diseases, but remains limited by the scarcity of suitable donors and the lack of reliable prolonged ... [more ▼]
IN RECENT years, pulmonary transplantation has become the treatment of choice for several end-stage lung diseases, but remains limited by the scarcity of suitable donors and the lack of reliable prolonged method of lung preservation.1 Transplantation of lung 6 hours postharvest leads to an increased incidence of primary graft dysfunction, due in part to ischemic damage of pulmonary cell structure and metabolism, and to acute reperfusion injury. However, very little is known about the real mechanisms of pulmonary cell injuries before, during, and after lung transplantation. During ischemia, the cytosolic and mitochondrial adenine nucleotide content falls,2,3 phospholipids are degraded, membrane permeabilities are increased, and the cytosolic levels of Na+, Ca2+ and phosphate are raised.4 Thus, cold and warm ischemia may induce cell dysfunctions and irreversible injuries responsible for necrosis. As mitochondia are believed to be the site of the determinants of irreversibility,5 the study of permanent oxidative phosphorylation damage after ischemia should be of great interest. The aim of this present study was to investigate the consequences of warm and cold ischemia on the oxidative phosphorylation of isolated lung mitochondria [less ▲]Detailed reference viewed: 14 (5 ULg)
Phylogenetic classification of the mitochondrial carrier family of Saccharomyces cerevisiae.
; ; et al
in Yeast (Chichester, England) (1997), 13
The screening of the open reading frames identified in the whole yeast genome has allowed us to discover 34 proteins belonging to the mitochondrial carrier family. By phylogenetic study, they can be ... [more ▼]
The screening of the open reading frames identified in the whole yeast genome has allowed us to discover 34 proteins belonging to the mitochondrial carrier family. By phylogenetic study, they can be divided into 27 subfamilies including ADP/ATP, phosphate and citrate carriers, putative oxoglutarate and GDC carriers and 22 new subfamilies. Topology predictions using the 'positive inside rule' approach have shown that the yeast carriers are similarly oriented with both extremities exposed to the cytosol. In each subfamily, a strict conservation of the charged residues in the six transmembrane alpha-helices is observed, suggesting a functional role for these residues and the existence of 27 functionally distinct carriers. [less ▲]Detailed reference viewed: 68 (9 ULg)
Type II to type I transformation of chronically stimulated goat latissimus dorsi muscle: a histoenzymological, biochemical, bioenergetic, and functional study.
; ; et al
in European Surgical Research = Europäische Chirurgische Forschung = Recherches Chirurgicales Européennes (1996), 28
Five goat latissimus dorsi muscles (LDM) were submitted to a progressive chronic electrostimulation program to reach an integrated understanding of the fast-to-slow transformation process in large mammals ... [more ▼]
Five goat latissimus dorsi muscles (LDM) were submitted to a progressive chronic electrostimulation program to reach an integrated understanding of the fast-to-slow transformation process in large mammals. LDM were regularly sampled and followed during a period of 8 months. Each sample was simultaneously assessed for histoenzymological study, myosin and LDH isoforms and bioenergetic capacities [NADH dehydrogenase cytochrome c oxidoreductase (NADH Cyt c OR), succinate dehydrogenase cytochrome c oxidoreductase (Succ Cyt c OR), cytochrome c oxidase (Cyt c Ox) and LDH]. Such muscles were also tested with and without completion of II to I transformation for their mechanical properties in isometric and isotonic strain gauge testing. The conversion of fast-to-slow myosin monitored by heavy chain (HC I) and light chain slow component (LC2s) began a few days after stimulation and was almost 100% after 100 days. The H-LDH isoforms evolved similarly but did not reach 100% conversion after 200 days. The activity of respiratory chain oxidases increased within 36 h but to a variable extent and peaked after 32 days, corresponding to a 75% transformation of myosin compared to initial levels. NADH Cyt c OR, Succ Cyt c OR, and Cyt c Ox, respectively increased 10-, 5- and 5-fold. These activities then significantly decreased before the completion of the myofibrillar transformation and reached a plateau with stable activities that remained 2- to 3-fold higher than the unstimulated LDM. LDH activity sharply decreased until day 62 (5-fold) and then plateaued. Functionally, muscle showed a reduced speed of contraction and moderate reduction in power output but had become fatigue-resistant. This study documents the transformation process in large mammals and suggests the dynamic relation between workload, aerobic-anaerobic metabolism and the contractile myofibrillar system. [less ▲]Detailed reference viewed: 16 (7 ULg)
Mitochondrial oxidative phosphorylation : in vitro and in situ effect of EGb 761
; DETRY, Olivier ; et al
in Packer, L.; Trabet, Maret G; Xin, Wenjuan (Eds.) Proceedings of the international symposium on natural antioxidants molecular mechanisms and health effects (1996)Detailed reference viewed: 7 (4 ULg)
Initial rate study of [C14]ADP uptake in ADP loaded mitoplasts and the kinetic mechanism of the ADP/ATP carrier
; ; Duyckaerts, Claire et al
in WEsterhoff, H. V.; Snoep, J.; Wijker, J. (Eds.) et al Biothermokinetics of the living cell (1996)Detailed reference viewed: 11 (1 ULg)
Determination of the respective contributions of the cytochrome and alternative oxidase pathway in Acanthamoeba catellanii
; ; et al
in Westerhoff, H.; Snoep, J.; Sluse, Francis (Eds.) et al Biothermokinetics of the living cell (1996)Detailed reference viewed: 4 (1 ULg)
Redox state behavior of membrane ubiquinone 9 and exogenos ubiquinone 2 determined by HPLC during respiration of Chlamydomonas reinhardtii mitochondria.
; ; Duyckaerts, Claire et al
in Westerhoff, H.; Snoep, J.; Sluse, Francis (Eds.) et al Biothermokinetics of the living cell (1996)Detailed reference viewed: 13 (3 ULg)
Mitochondrial metabolite carrier family, topology, structure and functional properties: an overview.
in Acta Biochimica Polonica. Polish. (1996), 43(2), 349-360
A set of metabolite carriers operates the traffic of numerous molecules consumed or produced in mitochondrial matrix and/or cytosolic compartments. As their existence has been predicted by the ... [more ▼]
A set of metabolite carriers operates the traffic of numerous molecules consumed or produced in mitochondrial matrix and/or cytosolic compartments. As their existence has been predicted by the chemiosmotic theory, the first challenge, in the late sixties, was to prove their presence in the inner mitochondrial membrane and to describe the various transports carried out. The second challenge was to understand their mechanisms by the kinetic approach in intact mitochondria (seventies). The third challenge (late seventies-eighties) was to isolate and to reconstitute the carriers in liposomes in order to characterize the proteins and to establish the concept of a structural and a functional family as well as some structure-function relationship with the help of primary sequences. Genetics, molecular biology and genomic sequencing bring the fourth challenge (nineties): a raising number of putative carriers becomes known only by their primary sequences but their functions have to be discovered. The actual challenge of the future is the elucidation of the ternary structure of carrier proteins that together with site-directed mutagenesis and kinetic mechanism will permit to advance in the understanding of molecular mechanisms of transport processes. [less ▲]Detailed reference viewed: 13 (4 ULg)
Mutations Affecting the Mitochondrial Genes Encoding the Cytochrome Oxidase Subunit I and Apocytochrome B of Chlamydomonas Reinhardtii
Colin, Martine ; ; Duby, Franceline et al
in Molecular & General Genetics [=MGG] (1995), 249(2), 179-84
Mitochondrial mutants of the green alga Chlamydomonas reinhardtii that are inactivated in the cytochrome pathway of respiration have previously been isolated. Despite the fact that the alternative oxidase ... [more ▼]
Mitochondrial mutants of the green alga Chlamydomonas reinhardtii that are inactivated in the cytochrome pathway of respiration have previously been isolated. Despite the fact that the alternative oxidase pathway is still active the mutants have lost the capacity to grow heterotrophically (dark + acetate) and display reduced growth under mixotrophic conditions (light + acetate). In crosses between wild-type and mutant cells, the meiotic progeny only inherit the character transmitted by the mt- parent, which indicates that the mutations are located in the 15.8 kb linear mitochondrial genome. Two new mutants (dum-18 and dum-19) have now been isolated and characterized genetically, biochemically and at the molecular level. In addition, two previously isolated mutants (dum-11 and dum-15) were characterized in more detail. dum-11 contains two types of deleted mitochondrial DNA molecules: 15.1 kb monomers lacking the subterminal part of the genome, downstream of codon 147 of the apocytochrome b (COB) gene, and dimers resulting from head-to-head fusion of asymmetrically deleted monomers (15.1 and 9.5 kb DNA molecules, respectively). As in the wild type, the three other mutants contain only 15.8 kb mitochondrial DNA molecules. dum-15 is mutated at codon 140 of the COB gene, a serine (TCT) being changed into a tyrosine (TAC). dum-18 and dum-19 both inactivate cytochrome c oxidase, as a result of frameshift mutations (addition or deletion of 1 bp) at codons 145 and 152, respectively, of the COX1 gene encoding subunit I of cytochrome c oxidase. In a total of ten respiratory deficient mitochondrial mutants characterized thus far, only mutations located in COB or COX1 have been isolated.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]Detailed reference viewed: 19 (4 ULg)
Mitochondrial oxidative phosphorylation injuries occurring in situ and in vitro.
; ; DETRY, Olivier et al
in Transplantation Proceedings (1995), 27Detailed reference viewed: 11 (3 ULg)
Localization and transmembrane topology of a new member of the mitochondrial carrier family, the yeast RIM 2 gene product
; Duyckaerts, Claire ; et al
in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1995)Detailed reference viewed: 19 (6 ULg)
Thiamine Deficiency--Induced Partial Necrosis and Mitochondrial Uncoupling in Neuroblastoma Cells Are Rapidly Reversed by Addition of Thiamine
Bettendorff, Lucien ; Sluse, Francis ; Goessens, Guy et al
in Journal of Neurochemistry (1995), 65(5), 2178-2184
Culture of neuroblastoma cells in a medium of low-thiamine concentration (6 nM) and in the presence of the transport inhibitor amprolium leads to the appearance of overt signs of necrosis; i.e., the ... [more ▼]
Culture of neuroblastoma cells in a medium of low-thiamine concentration (6 nM) and in the presence of the transport inhibitor amprolium leads to the appearance of overt signs of necrosis; i.e., the chromatin condenses in dark patches, the oxygen consumption decreases, mitochondria are uncoupled, and their cristae are disorganized. Glutamate formed from glutamine is no longer oxidized and accumulates, suggesting that the thiamine diphosphate-dependent alpha-ketoglutarate dehydrogenase activity is impaired. When thiamine (10 microM) is added to the cells, the O2 consumption increases, respiratory control is restored, and normal cell and mitochondrial morphology is recovered within 1 h. Succinate, which is oxidized via the thiamine diphosphate-independent succinate dehydrogenase, is also able to restore a normal O2 consumption (with respiratory control) in digitonin-permeabilized thiamine-deficient cells. Our results therefore suggest that the slowing of the citric acid cycle is the main cause of the biochemical lesion induced by thiamine deficiency as observed in Wernicke's encephalopathy. [less ▲]Detailed reference viewed: 38 (23 ULg)
Thiamine Deficiency in Cultured Neuroblastoma Cells: Effect on Mitochondrial Function and Peripheral Benzodiazepine Receptors
Bettendorff, Lucien ; Goessens, Guy ; Sluse, Francis et al
in Journal of Neurochemistry (1995), 64(5), 2013-2021
When neuroblastoma cells were transferred to a medium of low (6 nM) thiamine concentration, a 16-fold decrease in total intracellular thiamine content occurred within 8 days. Respiration and ATP levels ... [more ▼]
When neuroblastoma cells were transferred to a medium of low (6 nM) thiamine concentration, a 16-fold decrease in total intracellular thiamine content occurred within 8 days. Respiration and ATP levels were only slightly affected, but addition of a thiamine transport inhibitor (amprolium) decreased ATP content and increased lactate production. Oxygen consumption became low and insensitive to oligomycin and uncouplers. At least 25% of mitochondria were swollen and electron translucent. Cell mortality increased to 75% within 5 days. [3H]PK 11195, a specific ligand of peripheral benzodiazepine receptors (located in the outer mitochondrial membrane) binds to the cells with high affinity (KD = 1.4 +/- 0.2 nM). Thiamine deficiency leads to an increase in both Bmax and KD. Changes in binding parameters for peripheral benzodiazepine receptors may be related to structural or permeability changes in mitochondrial outer membranes. In addition to the high-affinity (nanomolar range) binding site for peripheral benzodiazepine ligands, there is a low-affinity (micromolar range) saturable binding for PK 11195. At micromolar concentrations, peripheral benzodiazepines inhibit thiamine uptake by the cells. Altogether, our results suggest that impairment of oxidative metabolism, followed by mitochondrial swelling and disorganization of cristae, is the main cause of cell mortality in severely thiamine-deficient neuroblastoma cells. [less ▲]Detailed reference viewed: 19 (9 ULg)
Fundamentals of transformed skeletal muscle used for cardiac assistance. An overview
; ; Sluse, Francis et al
in Research in Surgery (1995), 7Detailed reference viewed: 12 (6 ULg)
Overexpression of a novel member of the mitochondrial carrier family rescues defects in both DNA and RNA metabolism in yeast mitochondria.
; ; et al
in Molecular & General Genetics [=MGG] (1995), 246
The PIF1 and MRS2 gene products have previously been shown to be essential for mitochondrial DNA maintenance at elevated temperatures and mitochondrial group II intron splicing, respectively, in the yeast ... [more ▼]
The PIF1 and MRS2 gene products have previously been shown to be essential for mitochondrial DNA maintenance at elevated temperatures and mitochondrial group II intron splicing, respectively, in the yeast Saccharomyces cerevisiae. A multicopy suppressor capable of rescuing the respiratory deficient phenotype associated with null alleles of either gene has been isolated. This suppressor is a nuclear gene that was called RIM2/MRS12. The RIM2/MRS12 gene encodes a predicted protein of 377 amino acids that is essential for mitochondrial DNA metabolism and proper cell growth. Inactivation of this gene causes the total loss of mitochondrial DNA and, compared to wild-type rhoo controls, a slow-growth phenotype on media containing glucose. Analysis of the RIM2/MRS12 protein sequence suggests that RIM2/MRS12 encodes a novel member of the mitochondrial carrier family. In particular, a typical triplicate structure, where each repeat consists of two putative transmembrane segments separated by a hydrophilic loop, can be deduced from amino acid sequence comparisons and the hydropathy profile of RIM2/MRS12. Antibodies directed against the aminoterminus of RIM2/MRS12 detect this protein in mitochondria. The function of the RIM2/MRS12 protein and the substrates it might transport are discussed. [less ▲]Detailed reference viewed: 11 (1 ULg)
The N- and C-termini of the tricarboxylate carrier are exposed to the cytoplasmic side of the inner mitochondrial membrane.
; ; et al
in FEBS Letters (1995), 357
Polyclonal antibodies were raised in rabbits against two synthetic peptides corresponding to the N- and C-terminal regions of the rat-liver mitochondrial tricarboxylate carrier. ELISA tests performed with ... [more ▼]
Polyclonal antibodies were raised in rabbits against two synthetic peptides corresponding to the N- and C-terminal regions of the rat-liver mitochondrial tricarboxylate carrier. ELISA tests performed with intact and permeabilized rat-liver mitoplasts showed that both anti-N-terminal and anti-C-terminal antibodies bind only to the cytoplasmic surface of the inner membrane, indicating that both termini of the membrane-bound tricarboxylate carrier are exposed to the mitochondrial intermembrane space. Furthermore, tryptic digestion of intact mitoplasts markedly decreased the binding of anti-N-terminal and anti-C-terminal antibodies to the tricarboxylate carrier. These results are consistent with an arrangement of the tricarboxylate carrier monomer into an even number of transmembrane segments, with the N- and C-termini protruding toward the cytosol. [less ▲]Detailed reference viewed: 11 (1 ULg)